1. Field of the Invention:
The present invention relates to a complementary metal-oxide-semiconductor--emitter-coupled logic (CMOS-ECL) converter with a driver stage and an output transistor for the connection of a load, whereby an input of the CMOS-ECL converter is formed by an input of the driver stage and an output of the driver stage is connected to a control input of the output transistor, the drive stage being connected to a first terminal and to a second terminal for voltage supply, and the output transistor being connected between an output of the CMOS-ECL converter and the first terminal of the voltage supply, and wherein the driver stage contains at least one field effect transistor of the first conductivity type whose gate terminal is connected to the input of the driver stage and that is simultaneously connected between the output of the driver stage and the second terminal for the voltage supply.
2. Description of the Prior Art
ECL and CMOS circuits are widely used in semiconductor circuit technology. The ECL circuits have the shortest switching times of all logic families. These lie in the region of a few nanoseconds and, in part, also extend below one nanosecond. Complementary MOSFET transistors are utilized in CMOS circuits. The ohmic output load of the CMOS circuits is thereby extremely low because of the high input resistances. The switching time also becomes longer, the higher the capacitive output load. Given a greater capacitive output load, the switching time lies on the order of magnitude of about 10 nanoseconds and above.
In addition to MOS circuit technology, a bipolar CMOS (BICMOS) circuit technology has also been developed in recent years that is utilized particularly in time-critical and compact circuits. Advantages from the MOS circuit technology arise, as well as from the bipolar circuit technology, due to the utilization of BICMOS circuits. High packing densities and low static dissipated power that are characteristic, for example, of circuits from the CMOS circuit technology, a low offset voltage as well as an extremely high processing speed that are characteristic of circuits constructed in ECL or, respectively, bipolar circuit technology, are features that are favorable for the utilization of circuits in "BICMOS" circuit technology. Extremely high working speeds can definitely be achieved with the assistance of the "BICMOS" circuit technology, in that the circuit parts having higher processing speed are realized in ECL technology, but circuit parts less time-critical are realized in CMOS circuit technology.
Fast level converters or, respectively, output driver circuits are respectively required between these two circuit blocks.
FIG. 1 thereby illustrates a CMOS output driver in "BICMOS" circuit technology, and as is known in the art, that converts CMOS into the ECL level. It contains a driver stage with a following output transistor. As may be further seen from FIG. 1, the CMOS-ECL output driver has its input side connected to a internal chip CMOS standard inverter and has its output side terminated with an output load of 50 ohms. The matching between the internal chip CMOS standard inverter having low channel widths and the bipolar output transistor occurs here on the basis of a CMOS inverter to be suitable dimensioned as a driver stage. Although the base current to be supplied for the output transistor is adequately high given large MOS transistor widths of this driver, the internal chip CMOS standard inverter is simultaneously highly capacitively loaded before the driver stage.